Method for fusion of fractured or voided sternum post sternotomy

ABSTRACT

Disclosed herein are improved surgical techniques for repairing bone defects in a sternum during a sternotomy procedure and implants adapted for such techniques. In an exemplary embodiment, provided is a fusion strip made of an osteoconductive material and of a dimension that is especially adapted for improved repair of sternal bone defects.

BACKGROUND

The use of various forms of demineralized bone matrix (DBM) has been astandard practice in Orthopedic surgery for at least 30 years. DBM is anosteoconductive and osteoinductive material that resorbs and is replacedwith host bone (patient's bone) during the healing process. Its maincomponent, demineralized cortical bone matrix, is derived from donorhuman tissue (allograft bone) that has been aseptically processed andcontains various growth factors including osteoinductive proteins. MostDBM is finely granulated cortical bone, which is mixed with abiocompatible carrier that allows the product to exist in the form of aputty, paste, or gel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the use of a fusion strip embodiment in a sternotomyprocedure in a sternum having a defect.

FIG. 2 shows the positioning of a fusion strip embodiment into thedefect shown in FIG. 1.

FIG. 3 depicts the use of more than one fusion strip embodiment in asternotomy procedure in a sternum having a defect.

FIG. 4 shows the positioning of two fusion strips into the defect shownin FIG. 3.

FIG. 5 depicts a placement of a fusion strip into a sternal defect andproximate closure of sternal halves during a sternotomy procedure.

FIG. 6 depicts a sequential placement of a further fusion strip afterthe stage shown in FIG. 5.

FIG. 7 depicts an example of a fusion strip embodiment in perspectiveview.

FIG. 8 depicts an example of a fusion strip embodiment in perspectiveview.

FIG. 9 depicts a side view 9 a of an example of a fusion stripembodiment and a perspective view 9 b of the fusion strip embodimentshown in FIG. 9 a.

FIG. 10 depicts use of a varied-width fusion strip embodiment in asternotomy procedure.

FIG. 11 depicts placement of the varied-width fusion strip embodiment inthe defect shown in FIG. 10.

FIG. 12 shows a bottom perspective view of a fusion strip system thatincludes a fusion strip that is attached to a plate.

FIG. 13 shows a side perspective view of the embodiment shown in FIG.12.

FIG. 14A-B is a photograph of two different fusion strip embodimentsmade from demineralized cancellous bone.

FIG. 15 shows another embodiment of a fusion strip that has varied widthand thickness dimensions. FIG. 15a shows a side view of the width sideand FIG. 15b shows the side view of the thickness side.

FIG. 16 shows another embodiment of a fusions strip that has variedwidth and thickness dimensions.

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of ordinary skillin the art to which this disclosure belongs. All patents, applications,published applications and other publications are incorporated byreference in their entirety. In the event that there are a plurality ofdefinitions for a term herein, those in this section prevail unlessstated otherwise.

While DBM has been known, its use has been limited to specific fields ofmedicine. It has been realized that the use of DBM by cardiac surgeonsor plastic surgeons has not been developed. A main reason that DBMhistorically could not be used in the sternum is because most commonforms of DBM tend to migrate after placement in the bone.

Cadaveric tissue is a precious and unique material. The form and use ofcadaveric-derived allograft material is directly connected to availableharvesting and processing techniques as well as the natural architectureof the tissue itself. Accordingly, there are limits on the types ofproducts that can be produced from cadaveric tissue. Indeed, there aremultiple patents surrounding the production of new types of implantsthat are only made possible by new processing techniques.

Recent technical advancements have resulted in bone banks being able tocreate a new variation of DBM by harvesting specifically-sized strips ofcancellous bone and process them for use in surgery. Another newvariation is to machine cortical bone into shavings that are thencompressed into various shaped molds and demineralized. The resultantproduct can be uniquely shaped and utilized in spine, orthopedicsurgery, foot and ankle surgery, and Cranio-maxillofacial surgery, toname a few. These demineralized allograft bone products have no addedcarrier and thus exist as 100% DBM.

One aspect of the disclosure is the utilization of DBM or bone graftsubstitute strips of a unique size and configuration (hereinafterreferred to as fusion strips) that are adapted for safe use in thesternum of patients by cardiothoracic surgeons as a method to repairdefects or voids in the sternotomy site. There are limited sources ofthese strips; only a few bone banks in the US currently make thedemineralized cancellous allograft strips. It is believed that none ofthese tissue banks, or any orthopedic or cardiac company has developedthe use of demineralized cancellous strips or any other form of DBM inthe sternum for sternotomy procedures. According to a specificembodiment, disclosed herein is the use of demineralized allograft bone(e.g. cancellous or cortical) in a form of a strip for implementation inthe surgical wound to the sternum following open heart surgery.

The size of the size of the fusion strip that is particularly adaptedfor use in the sternum may be 3-12×45-60×3-8 mm(width×length×thickness). In a more specific embodiment, the dimensionof the fusion strip is approximately 5×50×5 mm or approximately 7×50×5mm. This size is currently made by only 2 bone banks in the US [BoneBank Allografts and Bacterin]. The term “approximately” as it applies todimensions means that each recited dimension may deviate up to 2 mm or10 percent, whichever is greater. Thus, for example, approximately 100mm means 100 mm or from 90 mm to 110 mm; or approximately 10 mm means 10mm or from 8 mm to 12 mm. Also contemplated is the use of fusion stripshaving a slightly larger width, e.g., 9-12×45-60×3-8 mm, or in a morespecific embodiment, the configuration is approximately10×50×5 mm orapproximately 12×50×5.

According to an alternative embodiment, the fusion strips are processed(e.g. cut) to produce a male and female notch in the lateral sides orends of the graft, thus creating a simple joint, similar to a puzzlepiece or wooden toy train tracks. This will then allow two or morepieces to be joined together with or without a biologically compatibleglue or suture, prior to implantation.

Technique:

Cardiac surgeons most commonly use a sternotomy technique (splitting thebreastbone with a powered saw) to gain access to the heart. Thebreastbone is ideally sawed longitudinally down the midline of thesternum (median sternotomy). At the end of the surgery, both halves ofthe sternum (hemi sternum) are approximated (brought back together) andsecured with monofilament stainless steel cerclage wire. There aremodified versions of the sternotomy technique that include a combinationof longitudinal and transverse incisions into the sternum as well. Somesurgeons use cables, or plates and screws to secure the sternum as analternative method. Most patients have adequately hard and robuststernal bone quality, which tends to heal well following surgery.However, there are increasing numbers of older and sicker patients inrecent years, who have poor sternal bone quality. Up to 15% of heartpatients have this problem. The fusion strip is most commonly used inheart patients who have osteoporosis, or other conditions that causetheir bone to degenerate, thus creating very soft or voided areas oftheir cancellous (spongy) sternal bone. It also may be used in thesternums of heart patients that have any type of fracture, gap or voidat the sternotomy site, not necessarily associated with osteoporosis.

The shorter, upper part of the human sternum is referred to as themanubrium, while the longer, central part is referred to as the sternalbody. The bottom part of the sternum is called the xyphoid process. Whena patient is a candidate for this fusion strip, typically 2 small pieces(7×50×5 mm) are placed longitudinally along the sternal body, in betweenthe sternotomy site.

The sternal body is usually more negatively affected by osteoporosisthan the manubrium. It is at the surgeon's discretion whether themanubrium needs be grafted with a fusion strip. If necessary, the larger(12×50×5 mm) fusion strip is placed in the manubrium in addition to the2 smaller pieces in the sternal body. So, 2 or 3 pieces are routinelyused on a typical case. In an alternative embodiment, a different sizingoption for treatment of the sternal body is provided: 7×45×5 mm. In thiscase, three pieces might be used from the xyphoid all the way to the topof the sternal body. And, this would total 4 pieces if the larger pieceis also used in the manubrium. This is all dependent on the dimensionsof the patient's sternum and severity of the voids.

Before implantation, each piece of bone graft is typically rehydratedfor several minutes in saline, blood, or bone marrow aspirate or someother suitable liquid, following the instructions from the bone bank.

Also, according to another embodiment, the fusion strip may includevaried dimensions along the length of the strip. For example, the fusionstrip may have the side profile that shows a section of the strip havingone width and another section that has a larger or smaller width. In aspecific example, the side profile of the fusion strip resembles apaddle. In an even more specific embodiment, the fusion strip comprisesa first section that is approximately 100 mm in length and approximately7 mm wide and section contiguous to the first section that isapproximately 50 mm long and approximately 12 mm wide.

EXAMPLE 1

Before implantation, in this example, the fusion strip needs to berehydrated, which is typically done by using saline, blood or some othersuitable fluid for a minimum of 5 minutes. Then once it is rehydratedand spongy, the graft is taken out of the saline and gently squeezedagainst a surgical towel, so as to remove most of the saline. The graftwill still remain spongy and pliable at this point. This is doneimmediately prior to implantation in the sternotomy site. Then, once itis placed into the site, following the technique described below, itwill absorb the bone marrow, accomplishing two tasks. It will wick up(absorb) live osteogenic cells from the marrow, which is critical toallow the bone healing cascade to initiate within the graft. Secondly,it acts as a hemostatic agent because the trabelcular structure of thecancellous bone graft fusion strip offers a perfect scaffold for bloodclots to form within.

If further hemostatic action is desired, the rehydrated fusion strip canbe soaked in a thrombin or fibrinogen solution, or anhydrous thrombinpowder or platelet gels can be applied to it before implantation. Otherpossible hemostatic agents that can be applied to this bone graftinclude various oxidized cellulose products, microcrystalline collagens,gelatins, or microporous polysaccharide hemospheres. Bone wax shouldalways be avoided for hemostasis in combination with the bone graft. Italso should not be applied to the edges of the sternal halves at thebeginning of the surgery. It may act as a permanent barrier andinhibitor of bone growth. The performance of the bone graft will beconstrained.

When the 1 to 4 fusion strips of are implanted, it is important thatthey form one long, continuous piece as it is placed. A big challengewith implanting the fusion strips onto the edge of a sternal half at thesternotomy site, is how to keep it in place until the sternum isapproximated. One must prevent the fusion strip from falling down fromthe edge of the sternal half onto the heart or somewhere else in themediastinum. The first described method is for the surgeon to place thefirst fusion strip with forceps along the affected edge of either theleft or right sternal half, and then to place 2 to 3 mattress stylesutures around or through the center of the fusion strip and through thecortices of the host bone so as to gently hold the graft in place. Thenthe second, third, and/or fourth fusion strip is contiguously placed andsutured in a similar fashion. It is important not to suture the fusionstrip too tightly, or else it will compress the strip, thus compromisingits ability to fill in the bone voids of the other sternal half, onceapproximation of the sternum has taken place. The cerclage wire orsternal cables can be placed in the sternum either before or afterplacement of the fusion strip, depending on the surgeon's preference.

A variation of this method uses biologically compatible glues or fibrintype sealants, or other hemostatic products, as described above, toadhere each piece of the fusion strip in position along one side of thesternal half in a similar fashion as the aforementioned mattress suturemethod or they can also be used to connect (glue) 2 or more fusionstrips before they are placed into the sternum. The puzzlepiece-fashioned joints will be machined by the bone bank onto eachfusion strip. This will create more surface area between the pieces,allowing better bonding of the glue. If suture is used to connect thepieces, this joint will serve as a junction point that will acceptplacement of the suture.

It should be borne in mind that the reference to sternal half or halvesis used in a broader sense to pertain to any section of the sternum thatis typically formed during a sternotomy and not to just a sectionrepresenting a one-halve of a sternum. Also, the sternum may, but notnecessarily be cut into more than two sections, or halves.

EXAMPLE 2

A second implantation method is to place each piece of the fusion strip,one at a time, into the sternotomy site while simultaneously tensioningthe wires. First, place all of the cerclage wire or cable in the sternumusing the surgeon's routine technique. Then the wires or cables aretensioned and the sternum is brought to within roughly 5 mm of beingfully approximated. At this point, the surgeon or assistant will useforceps to place the first piece of the fusion strip longitudinally inbetween the two sternal halves, making sure that the fusion strip isplaced into the realm of the voided cancellous bone. The first piece isusually implanted in the most superior portion of the affected sternalbone. Then, while holding the first piece in place with forceps, thatportion of the sternum is further approximated and the wires can becrossed and twisted once or twice to maintain approximation, thusholding the fusion strip in place. Then working inferiorly (down thesternum) the second and successive pieces are placed contiguously to thefirst piece with forceps using the aforementioned technique. Finally,all the wires are twisted, or the cables are tensioned in the routinemanner to fully approximate and secure the sternum.

EXAMPLE 3

In a variation of the method, each piece of the fusion strip (between 2and 4) after rehydration, may be wrapped in a thin layer of resorbablegauze-like material, which would roll them together in a cigar-likefashion. This could then be placed against one side of the sternal halfin the sternotomy site, as one unit, rather than three or four separatepieces. For example, a commonly available hemostatic product, Surgicel®original, from Ethicon Biosurgery could be used in this case. A 2×6 inchstrip, for example, of Surgicel® would be laid on a sterile towel. Eachrehydrated fusion strip would be placed linearly onto the Surgicel®strip. Then the fusion strips would be rolled one time to encapsulatethe them, like rolling a cigar. Excess Surgicel® material would betrimmed off at this point. It can also be rolled onto three sides of thefusion strips, leaving the portion of graft that bridges to the othersternal half uncovered. Then, the entire piece would be gently tuckedinto the voided area of the sternotomy site. The sternum would then beclosed in a routine manner, as described above.

EXAMPLE 4

Another variation of the above method would use an absorbable surgicaltape or mesh to gently fasten each piece of the fusion strip in placealong the sternotomy site. A small, narrow piece of the surgical tapewould go from the near cortex of the sternum down and around the fusionstrip and then to the underside of the far sternal cortex (similar toplacement of sutures).

EXAMPLE 5

A third method of implantation describes how to implant the fusion stripwhen the surgeon is also using plates and screws. Most plates areimplanted onto the sternum after the sternum is approximated withcerclage wire, as described above. In those instances, either of theaforementioned methods for implanting the fusion strip can be used priorto plate and screw implantation.

A newer generation of plates, specifically the Tritium™ Sternal CablePlate from Pioneer Surgical, includes a cable that goes through theplate and around the sternum. This cable is first placed around thesternum, in a similar fashion as a cerclage wire is implanted. Then thecable is tensioned and crimped to help approximate the sternum. Finally,the screws are placed into the plate. If the surgeon chooses to use thefusion strip in conjunction with a Tritium™ Sternal Cable Plate or anyother similar plate, the fusion strip may first be loosely sutured orglued to the underside of the plate. (see FIGS. 12 and 13) Then theplate is placed onto the desired portion of the sternum and the cable isthen tensioned following the standard technique.

Other Considerations

In each aforementioned method of implanting the fusion strip, theorientation of the strip against the edge of the sternotomy site isgenerally as follows: the width dimension is typically laid against theside of the bone where the void or gap is located. For purposes ofexplanation only, and not intended to limit the scope of the inventionin any way, when using a specific example, such as a 7×50×5 mm(width×length×thickness) fusion strip, the 7 mm dimension is laidagainst the side of the bone and covers from the near to the far cortex(superficial to deep), while the 5 mm dimension bridges in between theleft and right sternal halves, and the 50 mm portion runs up and downthe length of the sternum, in a superior/inferior direction. Ifnecessary, the fusion strip can be rotated 90 degrees, allowing the 7 mmdimension to bridge between both sides. If the size of the sternal bodyis quite large, then two to three of the 12×50×5 mm fusion strips shouldbe used instead of the smaller size. If the voids are large, the 12 mmportion can be rotated transversely to bridge between the left and rightsternal halves. If the voids are significant, separate fusion strips areplaced along both sides of the sternal halves at the sternotomy site. Ifany combination of transverse and median sternotomy techniques are used,either size fusion strip may be used to fill voids, at the surgeon'sdiscretion.

Another important use of the fusion strip is for treatment of sternalnon-unions. In these cases, the surgeon must reopen the sternum and pullout the old wires or cables. He must then debride the fibrous tissuewithin the fracture gap of the non-united bone. This debridement must bedone until the bleeding margins on the ends of the sternal bone areexposed. Very often a rasp must be also used to remove fibrous anddevitalized tissues. At this point the sternum is rewired andapproximated. In many instances, the edges of the sternal halves do notmeet together well (have gaps), because of the debridement process.Therefore, placing the fusion strip between the edges is warranted. Thefusion strip will compress if there is no gap, and will expand like asponge into any gaps along the edges of the sternal bone. Theimplantation technique in this case may be similar to that as mentionedabove. In this case, perhaps only one fusion strip may be necessary.

Synthetic calcium osteoconductive bone graft substitutes could bemachined into identical or longer lengths as the human allograft bonedescribed above. These bone substitute material composite grafts aretypically made from calcium sulphate or calcium phosphate materials.Synthetic bone substitutes are also made from the following: ceramichydroxyapatites, bioglasses, coralline hydroxyapatites, tricalciumphosphate, or bovine collagen, to name a few. They emulate humandemineralized cancellous bone, having a similar size interconnectedporosity, which is the scaffold for cellular ingrowth.

Alternatively, a cortical bone based DBM material formed from corticalbone pieces, such as shavings, that are compressed into various moldsmay be used instead of demineralized cancellous bone. Alternatively, thecortical bone based DBM material includes a physiologically acceptablecarrier such as, but not limited to, collagen, gelatin and/or lecithinand the like. The cortical bone based DBM may comprise 30-100 percentdemineralized cortical bone. In a more specific example, the corticalbone based DBM may comprise 90-100 percent demineralized cortical bone.A non-limiting representative example of a synthetic fusion strip forthe sternal body might be, for example, approximately 7×135×5 mm, whichis longer than what can be typically achieved from demineralizedcancellous bone. Various other heights and lengths could be made totreat patients with larger or smaller sternal dimensions.

Illustrated Examples

Turning to FIGS. 1 & 2, depicted is a sternum that has been split into afirst sternum section 108 and a second sternum section 109, such aswould occur in a sternotomy procedure. The first sternum section 108includes a void 112 that is present in the cancellous area of the bone.Such a void is a representative example of deficit that would be acriteria to determine a patient in need. An embodiment of a fusion strip110 is shown that is configured for placement in the void 112. Thefusion strip 110 in most instances will lay in the void without the needfor any particular securement step. However, in some cases it may beappropriate to hold the fusion strip onto the sternum section such asthrough the use of a compatable adhesive or through the use of sutures.FIG. 2 shows the fusion strip 110 positioned into the void 112 (hidden).Upon proper placement of the fusion strip 110, the first 108 and secondsternum sections are brought together to close upon the fusion strip 110and secured together through conventional techniques, such as, forexample, through the use of a cable, plate, sutures or staples.

In an exemplary embodiment, the fusion strip 110 may be made ofdemineralized bone matrix processed from a piece of cancellous bone. Itshould be borne in mind that allogenic sources of tissue are preciousand are inherently limited in making certain implant products that havethe appropriate osteoconductive and/or osteoinductive features and theappropriate dimensions for a given surgical technique. In the case ofallogenic sources of bone, obtaining a continuous piece of cancellousbone from a donor that can produce dimensions suitable for correctingcertain defects and or voids at a sternotomy site is not possible.Discussed herein are examples of suitable dimensions of a DBM fusionstrip that are achievable from a continuous piece of human cadavericcancellous bone. In some instances, depending on the size of the defector void, it is necessary to position more than one fusion strip into thecancellous area of the sternum.

FIG. 3 shows an embodiment that includes the implementation of twofusion strips 110 a and 110 b that are placed adjacent to eachother inthe sternotomy site between a first sternum section 208 and a secondsternum section 209 at a target void 212. FIG. 4 shows the placement ofthe fusion strips 110 a-b at the void 212 (hidden). As discussed above,upon positioning of the fusion strips 110 a-b, the first and secondsternum sections 208, 209 are closed upon the fusion strips 110 a-b andsecured together.

In a specific surgical technique embodiment, a first fusion strip isplaced in the void or defect and the proximate region of sternumsections are brought together by the wire to “squeeze” in the fusionstrip at that location. Following this tightening, the next fusion stripis placed adjacent to the end of the first fusion strip. Once this nextfusion strip is properly placed, the proximate region of the sternumsections are brought together around the next fusion strip portion. Itshould be noted that at each region of the sternum where a fusion stripis placed, one or more fusion strips could be put in that location. Forexample, a fusion strip could be put in the void of one sternum halfportion and an opposing fusion strip could be put in a void on theopposing sternum half portion across from the other. This depends on theseverity of the gaps or voids and the surgeon's discretion. An exampleof the sequential surgical technique is shown in the photographs of inFIGS. 5 and 6. Also shown in FIGS. 5 and 6 is an example of securementof the first and second sternum sections using a cable 120 technique.

FIG. 14 shows different fusion strip embodiments A and B. These fusionstrip embodiments represent demineralized bone matrix (DBM) (cancellous)derived from allograft bone. Typically, the DBM is obtained fromprocessed cancellous bone, as this produces an architecture that isparticularly conducive for bone conduction and induction at a sternotomyrepair site. As noted above, there is a limit on the dimensions forwhich allogenic bone can produce. For human cancellous bone, thedimensions that can be produced for a fusion strip embodiment typicallyfall within the following: 3-20×45-60×3-8 mm (width×length×thickness,represented as w₁, l₁, and t₁, respectively in the fusion stripembodiment 710 shown in FIG. 7) due to anatomical and size limitations.To produce DBM fusion strips from a continuous cancellous bone that havea greater length, these would need to be obtained from xenogenicsources, such as horses or cows that have longer bones. Thus, in anotherembodiment, the fusion strip used in certain method embodiments is oneproduced from demineralized cancellous bone obtain from a xenogenicsource. The xenogenic based fusion strip may have a dimension of3-8×65-200×3-8 mm (width×length×thickness).

As noted above, certain bone substitute material and/or cortical bonebased DBM material may be shaped and formed to possess dimensions thatexceed the limits presented by human cancellous bone. FIG. 8 shows anexample of a fusion strip 810 that has dimensions exceeding that whichis attainable by a continuous piece of human cancellous bone. In thisexample, l₁ is 80-120 mm, w₁ is 3-20 mm, and t₁ is 3-20 mm. Fusion strip810 would be particularly useful to repairs defects or voids that extenda great length of the sternum. Fusion strip would typically need to bemade from a bone substitute material and/or cortical bone based DBMmaterial.

FIG. 9 shows an example of a fusion strip embodiment 310 that has avariable width. FIG. 9a shows a side view of the embodiment 310, wherethe embodiment 310 has a first width w₁ that may be 9-17 mm. In aspecific embodiment, w₁ is 11-13 mm, or in a more specific embodiment itis approximately 12 mm. The embodiment 310 has a first length l₁ thatmay be 30-100 mm. In a specific embodiment, l₁ is 40-60 mm, and in amore specific embodiment it is approximately 50 mm. The embodiment 310has a second length l₂ that may be 65 mm-150 mm. In a specificembodiment, l₂ is 80-135 mm, and in a more specific embodiment it isapproximately 100 mm. The embodiment 310 has a second width w₂ that is3-10 mm. In a specific embodiment, w₂ is 4.5-8.5 mm and morespecifically is approximately 7 mm. Shown in 9 b is a perspective viewof the fusion strip embodiment 310. The fusion strip 310 has a firstthickness t₁ that is 3-10 mm. In a specific embodiment, t₁ is 4-8.5 mmand in a more specific embodiment, t₁ is approximately 5 mm. In analternative embodiment, the transition from w₁ to w₂ along the length ofthe strip may be a gradual taper as opposed to an orthogonal more abrupttransition.

FIG. 15 shows another embodiment 510 that has varied dimensions for bothwidth and thickness dimensions. As shown in FIG. 15a , which is a sideview showing the width dimension, the fusion strip 510 includes a firstwidth w₁ that may be 9-17 mm. In a more specific embodiment, w₁ isapproximately 12 mm. The fusion strip 510 includes a second width w₂that may be 3-10 mm. In a specific embodiment, w₂ is approximately 7 mm.FIG. 15a also shows that the length l₁ of the fusion strip 510 thatpertains to w₁ may be 30-100 mm. In a specific embodiment, l₁ isapproximately 50 mm. The length l₂ of the fusion strip 510 pertaining tow₂ may be 65-150 mm. In a specific embodiment, l₂ is approximately 100mm. As can be seen, the transition wt from the first width w₁ to thesecond width w₂ is a gradual taper. It will be understood that thetransition wt could be more abrupt such as an orthogonal transition.Shown in FIG. 15b is a different side view of the fusions trip 510showing the thickness. The fusions trip 510 includes a first thicknesst₁ that may be 3-10 mm. In a specific embodiment, t₁ is 5 mm. The fusionstrip 510 includes a second thickness t₂ that may be 5-12 mm. In aspecific embodiment, t2 is approximately 8. The transition from t₂ tot₁, tt₁ and tt₂ is a gradual taper. This could alternatively be a moreabrupt transition for tt₁ and/or tt₂.

FIG. 16 is a side view showing the width dimension of an alternativeembodiment 610 of a fusion strip. The fusion strip 610 includes a w₁ andw₂ similar to that described for 510 above, with similar dimensions. Asshown in FIG. 16, the transition from w₁ to w₂ is a gradual taper onboth sides as noted in tt₁ and tt₂. The taper occurs proximate to theintersection of l₁ and l₂. Regarding the thickness dimension of 610, itfollows the dimensions that are discussed for 510 in FIG. 15 b.

Turning to FIGS. 10 & 11, depicted is a sternum that has been split intoa first sternum section 308 and a second sternum section 309. The firststernum section 308 includes a void 312 that is present in thecancellous area of the bone. In this example, the void is present atsternal body 319 as well as the manubrium 320 (which is typicallythicker than the sternal body). Such a void is a differentrepresentative example of deficit that would be a criteria to determinea patient in need. The fusion strip 310 includes a first section 311 anda section section 313, with the first section 311 being wider. FIG. 11shows the fusion strip 310 positioned into the void 312 (hidden). Thefirst section 311 sits in the part of the void 312 that is present inthe manubrium 320, and the second section sits in the part of the void312 that is present in the sternal body 319.

FIG. 12 shows a bottom perspective view of a fusion strip system 400.The system 400 includes a fusion strip 410 that is associated with aplate 412. When two sections of a sternum are ready to be closedtogether, the plate 412 can assist in securing the two sections togetherwhile also facilitating repair of a defect or gap in the sternum byprovision of the fusion strip 410. FIG. 13 shows a side perspective viewof the system 400.

The specific fusion strip embodiments illustrated in the drawingsrepresent cuboidal shapes. However, in light of the teachings herein,those skilled in the art would understand that the fusion strips maytake different shapes and forms, including but not limited to, acylindrical shape, triangular prism shape or be generally cuboidal withrounded edges. For these alternative shapes, the dimensions(width×length×thickness) would generally apply, e.g., width would be theplane that abuts the void or gap in the sternum, length would be theplane that traverses down the sternum, and thickness would be the planethat extends out from gap, void or other defect.

It should be borne in mind that all patents, patent applications, patentpublications, technical publications, scientific publications, and otherreferences referenced herein and in the accompanying appendices arehereby incorporated by reference in this application to the extent notinconsistent with the teachings herein.

It is important to an understanding to note that all technical andscientific terms used herein, unless defined herein, are intended tohave the same meaning as commonly understood by one of ordinary skill inthe art. The techniques employed herein are also those that are known toone of ordinary skill in the art, unless stated otherwise. For purposesof more clearly facilitating an understanding the invention as disclosedand claimed herein, the following definitions are provided.

While a number of embodiments have been shown and described herein inthe present context, such embodiments are provided by way of exampleonly, and not of limitation. Numerous variations, changes andsubstitutions will occur to those of skilled in the art withoutmaterially departing from the invention herein. For example, the presentinvention need not be limited to best mode disclosed herein, since otherapplications can equally benefit from the teachings. Also, in theclaims, means-plus-function and step-plus-function clauses are intendedto cover the structures and acts, respectively, described herein asperforming the recited function and not only structural equivalents oract equivalents, but also equivalent structures or equivalent acts,respectively. Accordingly, all such modifications are intended to beincluded within the scope of this invention as defined in the followingclaims, in accordance with relevant law as to their interpretation.

What is claimed is:
 1. A fusion strip for use in repairing a bone defectcomprising: a body having a first end and a second opposite the firstend and varied dimensions between said first and second ends, whereinsaid body comprises a first portion having a dimension of9-17×30-100×3-10 (width×length×thickness) and a second portion having adimension of 3-10×65-150×3-10 (width×length×thickness).
 2. The fusionstrip of claim 1, wherein said fusion strip is made of anosteoconductive material.
 3. The fusion strip of claim 1, wherein saidfirst portion has a dimension of 11-13×40-60×4.5-8.5 mm(width×length×thickness).
 4. The fusion strip of claim 1, wherein saidsecond portion has a dimension of 4.5-8.5×80-120×4.5-8.5 mm(width×length×thickness).
 5. The fusion strip of claim 1, wherein saidfirst and second portions are cuboidal shaped.
 6. A method for closing asternum separated into at least a first sternum section having a firstsurgical cut site and a second sternum section having a second surgicalcut site in a patient in need thereof, wherein the sternum has amanubrium defect and a sternal body defect, the method comprising: i)positioning a fusion strip comprising a body having a first end and asecond opposite the first end and varied dimensions between said firstand second ends, wherein said body comprises a first portion having adimension of 9-15×30-100×3-10 (width×length×thickness) and a secondportion having a dimension of 3-10×65-150×3-10 (width×length×thickness),and wherein said first portion is positioned in the manubrium defect andthe second section is positioned in the sternal body defect; and ii)after positioning, urging together said first and second sternumportions such that said first and second surgical cut sites are broughttogether with said fusion strip being in contact with either or both ofsaid first or second surgical cut sites.
 7. The method of claim 6,wherein said bone defect is a void or fracture.
 8. A fusion strip foruse in repairing a bone defect comprising: a body having a first end anda second opposite the first end and varied dimensions between said firstand second ends, wherein said body comprises a first portion and asecond portion having different dimensions, wherein the first portionhas a width that is larger than the width of the second portion and thefirst portion has a thickness that smaller than the thickness of thesecond portion.
 9. The fusion strip of claim 8, wherein the firstportion has a dimension of 9-17×30-100×3-10 (width×length×thickness) anda second portion having a dimension of 3-10×65-150×5-12(width×length×thickness).
 10. The fusion strip of claim 9, wherein saidfirst portion has a dimension of approximately 12×50×5 mm.
 11. Thefusion strip of claim 9, wherein said second portion has a dimension ofapproximately 6×100×10 mm.
 12. The fusion strip of claim 9, furthercomprising a tapered transition from a larger dimension to a smallerdimension.
 13. The fusion strip of claim 8, wherein either said first orsecond portions are cuboidal.
 14. A method for closing a sternumseparated into at least a first sternum section having a first surgicalcut site and a second sternum section having a second surgical cut sitein a patient in need thereof, wherein the sternum has a manubrium defectand a sternal body defect, the method comprising: i) positioning afusion strip comprising a body having a first end and a second oppositethe first end and varied dimensions between said first and second ends,wherein said body comprises a first portion and a second portion havingdifferent dimensions, wherein the first portion has a width that islarger than the width of the second portion and the first portion has athickness that smaller than the thickness of the second portion, andwherein said first portion is positioned in the manubrium defect and thesecond section is positioned in the sternal body defect; and ii) afterpositioning, urging together said first and second sternum portions suchthat said first and second surgical cut sites are brought together withsaid fusion strip being in contact with either or both of said first orsecond surgical cut sites.
 15. The method of claim 14, wherein the firstportion has a dimension of 9-17×30-100×3-10 (width×length×thickness) anda second portion having a dimension of 3-10×65-65-150×5-12(width×length×thickness).
 16. The method of claim 14, wherein said firstportion has a dimension of approximately 12×50×5 mm.
 17. The method ofclaim 14, wherein said second portion has a dimension of approximately6×100×10 mm.
 18. The fusion strip of claim 1, wherein the fusion stripis associated with a plate.
 19. The fusion strip of claim 8, wherein thefusion strip is associated with a plate.
 20. The fusion strip of claim1, wherein the fusion strip is comprised of a bone substitute materialand/or cortical bone based DBM material.
 21. The fusion strip of claim8, wherein the fusion strip is comprised of a bone substitute materialand/or cortical bone based DBM material.